Classical configurations of strings and shapes of membranes in equilib
rium are defined by a nonlinear equation. It is shown that this equati
on has a simple form in terms of the inverse mean curvature and densit
y of squared mean curvature. Broad variety of its solutions (in partic
ular, kink, vortex and solitons) and corresponding possible shapes are
given, Anew type of degeneracy of membrane shapes and string configur
ations via the integrable Veselov-Novikov equation is discussed. (C) 1
997 Elsevier Science B.V.